Install teken.h for userland.

Part of VT(9) project merge.
Reviewed by:	nwhitehorn
MFC_to_10_after:	re approval

Sponsored by:	The FreeBSD Foundation

etc/mtree/BSD.include.dist

@@ -329,6 +329,8 @@
     ..
     sys
     ..
+    teken
+    ..
     ufs
         ffs
         ..

include/Makefile

@@ -225,6 +225,9 @@ copies:
 	cd ${.CURDIR}/../sys/rpc; \
 	${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m 444 types.h \
 	    ${DESTDIR}${INCLUDEDIR}/rpc
+	cd ${.CURDIR}/../sys/teken; \
+	${INSTALL} -C -o ${BINOWN} -g ${BINGRP} -m 444 teken.h \
+	    ${DESTDIR}${INCLUDEDIR}/teken
 
 symlinks:
 	@${ECHO} "Setting up symlinks to kernel source tree..."